package PTA2.ti1101;

import java.util.Scanner;

/**
 * @author Lenovo
 */

public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int number=scanner.nextInt();
       if(number>=0&&number<=15){
           String hex=Integer.toHexString(number).toUpperCase();
           System.out.println(hex);
       }else {
           System.out.println("Invalid input");
       }
       scanner.close();
    }
}